Not getting Django paypal IPN handshake

Question

I am trying to implement Django- PayPal in my project , now it has been 3 days , I am still stuck on this , I don't understand how we perform IPN handshake, I am receiving a signal from PayPal after payment but what is the next step after this , really frustrated there are no clear docs about this process help needed , thanks in advance

Signals.py

def show_me_the_money(sender, **kwargs):
    ipn_obj = sender
    if ipn_obj.payment_status == ST_PP_COMPLETED:
      

        

        # WARNING !
        # Check that the receiver email is the same we previously
        # set on the `business` field. (The user could tamper with
        # that fields on the payment form before it goes to PayPal)

        if ipn_obj.receiver_email != settings.PAYPAL_RECEIVER_EMAIL:
        # Not a valid payment
            print('reciever mail is diff')
            print(ipn_obj.receiver_email)
            

        # ALSO: for the same reason, you need to check the amount
        # received, `custom` etc. are all what you expect or what
        # is allowed.

        # Undertake some action depending upon `ipn_obj`.
        if ipn_obj.custom == "premium_plan":
            price = ...
        else:
            price = ...

        if ipn_obj.mc_gross == price and ipn_obj.mc_currency == 'USD':
            ...
        else:
            pass
            #...
            



valid_ipn_received.connect(show_me_the_money)

Urls.py

path('payment/',PaymentProcess.as_view(),name='payment-process'),  
path('payment_redirect/',Payment.as_view(),name='payment-redirect'),  
path('createorder/',CreateOrderView.as_view(),name='create-order'),  
#  Paypal IPN url ------------------

re_path(r'^paypal/', include('paypal.standard.ipn.urls')),
path('payment_done', payment_done,name='payment_done'),

I mean where should the below code reside or do I even need to process it, as I see other resources doing it , they are sending Response back to Paypal as confirming the payment https://github.com/paypal/ipn-code-samples/blob/master/python/paypal_ipn.py

verify_url = settings.VERIFY_URL_TEST
            print ('content-type: text/plain')
            print ()
            print('SIgnal form paypal')
    
            param_str = sys.stdin.readline().strip()
            print(param_str)
            params = urllib.parse.parse_qsl(param_str)
    
            params.append(('cmd', '_notify-validate'))
    
            print(params)
    
            headers = {'content-type': 'application/x-www-form-urlencoded',
               'user-agent': 'Python-IPN-Verification-Script'}
    
    
            r = requests.post(verify_url, params=params, headers=headers, verify=True)
            r.raise_for_status()
            print(r)